Are Probiotics Safe in Pregnancy?
Yes, probiotics are safe for use during pregnancy and lactation in healthy women, with the overwhelming evidence showing no increased risk of adverse maternal or fetal outcomes. 1, 2
Safety Evidence
The safety profile of probiotics during pregnancy is well-established through multiple lines of evidence:
Most probiotics are derived from fermented foods with a long history of safe consumption or from microbes that naturally colonize humans, and both the European Food Safety Authority (EFSA) and U.S. Food and Drug Administration (FDA) consider common probiotic species safe for the general population. 1
A systematic review and meta-analysis of 27 randomized controlled trials found that probiotic supplementation during pregnancy neither increased nor decreased the risk of preterm birth <37 weeks (RR 1.08,95% CI 0.71-1.63) or preterm birth <34 weeks (RR 1.03,95% CI 0.29-3.64). 3
Probiotic supplementation is rarely systemically absorbed when used by healthy individuals, and meta-analyses conducted with women during the third trimester of pregnancy did not report an increase in adverse fetal outcomes. 4
A 2021 systematic review specifically examining adverse effects found that probiotics and prebiotics are safe for use during pregnancy and lactation, with no serious health concerns to mother or infant. 2
Documented Benefits
Recent high-quality evidence demonstrates actual benefits rather than just safety:
A 2025 randomized controlled trial showed significantly fewer infections in pregnant women taking probiotics (8 vs. 18 women with one or more infections, p=0.05), and infants in the probiotic group had fewer days with infections during the first month of life (4.7 vs. 10.5 days, p=0.03). 5
Probiotics administered both prenatally to the pregnant mother and postnatally to the child reduced the risk of atopy (RR 0.71,95% CI 0.57-0.89) and food hypersensitivity (RR 0.77,95% CI 0.61-0.98). 6
Important Precautions and Contraindications
While safe for healthy pregnant women, certain high-risk populations require careful evaluation:
Avoid probiotics in immunocompromised patients, those with damaged intestinal mucosa, patients with central venous catheters, cardiac valvular disease, or short-gut syndrome. 1, 7
Serious adverse effects from probiotics are rare but have been documented in vulnerable populations, including cases of bacterial sepsis linked to lactobacilli supplements and death from gastrointestinal mucormycosis in a preterm infant from mold contamination. 6
Saccharomyces boulardii should be used with caution as it has been associated with fungemia in critically ill and immunocompromised patients. 1, 7
Practical Recommendations for Product Selection
Choose well-studied strains like Lactobacillus rhamnosus (now reclassified as Lacticaseibacillus rhamnosus), which have been extensively studied and have good safety profiles. 1
Always verify the precise bacterial identity at the strain level when selecting a probiotic, as claims for medical benefits can only be made for the specific strains in which they have been demonstrated. 6, 1
Be aware that probiotic quality varies—the amount of dead bacteria in a preparation is inversely proportional to product quality. 1
Consider products deposited at a biodepository such as the American Type Culture Collection (ATCC) for quality assurance. 1
Exercise caution with products containing extremely high concentrations of bacteria (450-900 billion bacteria per dose), as safety becomes more sensitive with these formulations. 6, 1
Common Pitfalls to Avoid
Do not assume all probiotic products are equivalent—effects are strain-specific, and safety findings for one formulation should not be generalized to other products. 6
Do not use probiotics in patients with predicted severe acute pancreatitis, as treatment with multispecies probiotic preparations has been associated with increased mortality risk in this specific population. 6
Be aware that one study reported increased risk of vaginal discharge and changes in stool consistency (RR 3.67,95% CI 1.04-13.0) when administering Lactobacillus rhamnosus and L. reuteri, though this does not pose serious health concerns. 2